<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    * {
      padding: 0;
      margin: 0;
    }
    html,body {
      width: 100%;
      height: 100%;
    }
    iframe {
      width: 100%;
      height: 90%;
    }
    .navList {
      height: 10%;
      padding-top:20px;
      margin-right: 10px;
    }
  </style>
</head>
<body>
  <nav class="navList">
    <a href="https://www.jd.com" target="A">京东</a>
    <a href="https://www.taobao.com" target="A">淘宝</a>
    <a href="https://www.baidu.com" target="A">百度</a>
  </nav>

  <iframe src="https://www.jd.com" frameborder="0" name="A" ></iframe>
  <!-- <iframe src="https://www.jd.com" frameborder="0"></iframe> -->
  <script>
    // SPA(Single Page Application) 单页面应用
    // - 基于iframe页面嵌套在父页面中模拟出单页面的效果，但是他的本质还是多页面
  </script>
</body>
</html>